How to Choose Your First Dive Computer: A Buyer's Checklist

What should you look for in a first dive computer?

Start with the diving you expect to do over the next year, then buy the computer that shows that information most clearly. A new diver making no-stop dives on air or nitrox needs a readable screen, conservatism settings they understand, a single-gas nitrox mode and a battery plan that fits how they travel. Everything else is optional.

We have not tested the models named in this guide. Every spec comes from the manufacturer's own manual or store page, and each model appears as an example of a feature, not as a recommendation. The table below matches common situations to the feature that solves them. For the background on algorithms and tables, see our dive computers and decompression guides.

Can you read the screen at depth?

Readability is the one feature no setting can fix, so test it first. Screens come in two families: segment LCDs with fixed digit shapes, and dot-matrix or color LCDs that can show more data and larger text.

Some manufacturer figures: the Shearwater Peregrine has a 2.2 inch (5.59 cm) full color LCD at 320 x 240 pixels with an always-on LED backlight, and Shearwater rates it at 30 hours per charge at medium brightness. The Scubapro Luna 2.0 AI uses a high-contrast black and white matrix-segment display. Suunto sells the Zoop Novo on its big, clear display with backlight, and the Zoop Novo manual notes that the backlight and buzzer switch off once the low-battery warning appears.

In the shop, hold the unit at arm's length, switch the backlight on and off, and read depth, dive time and NDL without squinting. If your mask has prescription lenses, test with the same correction.

Then decide where it lives. A wrist unit sits in your line of sight. A console hangs on the high-pressure hose next to the pressure gauge, so you lift it to read it. Watch-style computers double as everyday watches: Garmin lists the Descent G1 at up to 21 days in smartwatch mode and up to 25 hours in dive mode, and Oceanic rates its Oceanic+ app on the Apple Watch Ultra to 40 m (130 ft).

Which conservatism settings should a new diver look for?

Buy for conservatism settings you understand, not for an algorithm name. The model sets the baseline. The setting you choose decides how much margin sits on top of it, and Garmin's manual puts the trade plainly: higher conservatism gives a shorter bottom time and a longer ascent.

The menus look different by brand. The Suunto Zoop Novo has a three-step personal adjustment (0 for ideal conditions, 1 and 2 for more conservative) plus an altitude setting with bands for 0-300 m, 300-1,500 m and 1,500-3,000 m. The Shearwater Peregrine uses gradient factor presets: Low 45/95, Med 40/85 (the default) and High 35/75, plus a custom option. The Mares Genius defaults to 85/85 and has recreational presets down to 50/60.

Two checks matter more than the model name. First, count the button presses needed to change conservatism before a dive. Second, find out what the computer does after a mistake. The Zoop Novo locks its algorithm for 48 hours if you skip a required decompression stop for more than 3 minutes, leaving you without decompression data for two days. The Peregrine manual lists no lockout for missed deco stops.

Expect brands to disagree. A 2014 chamber test of 43 computer models at default settings found considerable variation in the no-stop time allowed at every depth tested. DAN points out the benefit of diving with people whose computers use a similar model and settings.

Do you need nitrox and multi-gas modes?

You need single-gas nitrox, and even entry-level computers have it. Check the range rather than the label. The Zoop Novo takes one gas at 21-50% oxygen with a default PO2 limit of 1.4 bar. The Peregrine's single-gas Nitrox mode goes to 40%, and its 3 GasNx mode holds three gases up to 100% oxygen for light decompression diving. The Garmin Descent G1 multi-gas mode accepts 5-100% oxygen and up to 11 extra gases, which is technical diving territory.

One detail catches new nitrox divers. On the Zoop Novo, a mix set to 22% or more stays set until you change it; it does not return to air on its own. Check the O2 value before every dive.

Use a known number to confirm you set it right. EAN32 at a 1.4 bar limit gives a maximum operating depth of 33.7 m (about 110 ft) in our nitrox calculator, and the computer's MOD warning should appear at about the same depth.

Multi-gas modes only earn their cost once you start decompression training. With no such course planned, a single-gas computer covers your diving.

Is air integration worth it on a first computer?

Usually not yet, because it adds real cost. On Shearwater's US store the Peregrine TX costs $760 without a transmitter, against $580 for the plain Peregrine. A transmitter screws into a high-pressure port on your first stage and sends tank pressure to the computer, which then estimates how long your gas will last at your current breathing rate.

Makers name that estimate differently. Scubapro's Luna 2.0 AI shows remaining bottom time (RBT) and treats your set reserve pressure, adjustable between 20 and 120 bar, as an empty tank. The Peregrine TX pairs with up to 4 transmitters and shows gas time remaining. Range is short: Scubapro gives its Smart transmitter about 1.5 m (5 ft).

Without air integration you keep a mechanical pressure gauge on the hose. Garmin and Suunto both tell you to carry backup instruments, including a pressure gauge, so a non-integrated computer does not remove anything from your kit. You can still work out gas duration from your logged dives with our SAC calculator.

Rechargeable, coin cell or AA battery?

Pick the battery type by where you dive. Rechargeables suit divers who already travel with chargers. User-replaceable cells suit remote trips. Service-center batteries suit divers who can plan a shop visit before a trip.

Rechargeables need care in storage. Shearwater tells Peregrine owners to charge to 100% before storing the computer and to top it up every 3 months, because a fully drained lithium-ion battery can be damaged. Coin cells need care at the seal: Suunto sends Zoop Novo battery changes to an authorized service center and does not cover defects caused by improper battery installation under warranty.

Gauge and freedive modes: check the lockout rules

Gauge mode turns the computer into a depth gauge and timer with no tissue tracking, so makers restrict normal diving afterwards, each with a different rule. Read it before you use gauge mode in a pool session or on a course, because it can keep the computer out of normal diving for one or two days.

Freediving modes carry their own rules. The Zoop Novo's Free mode starts a dive at 1.2 m, ends it above 0.9 m and samples every 2 seconds by default. The Luna 2.0 AI locks scuba mode for 12 hours after apnea dives shallower than 5 m and for 24 hours after deeper ones. The Garmin G1 has separate Apnea and Apnea Hunt modes, the second tuned for spearfishing. If you snorkel or freedive on the same trips as you scuba dive, check these locks before buying.

Read the manual and check firmware and service before you pay

Download the manual before you buy. Every manual used for this guide is a free PDF from the maker, and page count is a fair hint at menu depth: 41 pages for the Suunto Zoop Novo, 52 for the Shearwater Peregrine, 83 for the Scubapro Luna 2.0 AI and 134 for the Garmin Descent G1, which also covers GPS and smartwatch features.

In the manual, find three things: how to change conservatism, how to set a nitrox mix, and what happens after a missed stop. DAN's advice is to know which buttons make the computer work and which decompression model it uses.

Then check the support side. The Peregrine takes firmware upgrades over Bluetooth and uploads logs to Shearwater Cloud. The Luna 2.0 AI has user-updatable firmware. Suunto gives the Zoop Novo a maintenance cycle of 200 dives or two years. Ask a local dealer whether they handle battery changes and servicing for the brand you pick, and check that the log download works with the app you plan to use to log your dives.

How much does a first dive computer cost?

Manufacturer list prices fall into rough tiers. The cheapest example here lists at $299 and the technical example at $1,195. The table uses US list prices from each maker's own store or launch announcement. Prices change and vary by country, so treat them as anchors.

For a first computer, the entry and middle tiers cover no-stop recreational diving on air and nitrox. Pay for the next tier when its feature fixes a problem you already have, such as poor close-up vision or a technical course on the calendar.